Paying musicians

Hi,

Client of mine works as a musician and often gets paid in cash. From the cash income that he receives he often has to pay his fellow musicians so I was wondering what the easiest method of paying his fellow musicians?

I was thinking of suggesting that everytime he pays someone in cash that he gets them to sign a receipt saying that they have received the cash and that they are responsible for their own tax affairs.

Would this be sufficient or are there any other suggestions?

Thanks

Matt